Definition(s)
"Canon": Published material on Charted Space which is binding for future publishers of Traveller material.

Status of This Post. Marc Miller's reviewed this several times and actually did approve it. This probably opens more questions than it answers. A recent T5 discussion brought a few additions to the NOT CANON list.

Preamble. I'm not speaking for Marc here; I'm drawing from personal experience and observation to infer basic facts to assist. If I do speak for Marc online, I'll preface the post with "Marc is asking..." or "Marc wants...", or something similar. Rob Eaglestone also does this. That doesn't mean Rob or I have any special status. If I was writing material for the Spinward Marches, I'd probably have Hans Rancke review it before giving it to Marc for review, because I trust his knowledge of things I've forgotten.

So, bearing all of that in mind, here's some simple facts about Traveller canon:

1. It is, at any given moment, what Marc decides.
2. Marc reserves the right to change his mind.
3. The GURPS Traveller universe (GTU?) and the Official Traveller Universe overlap; exactly where they overlap is questionable, depending on who's asking the questions.
4. The precedent of "mostly recently published source" applies, unless that newer source is wrong about something; it happens.
5. Never, ever assume that current licensees are not canon; rather, current licensees are always canon, unless they print something wrong.
6. Marc decides who is wrong.
7. There's no order to the six rules above.

That's pretty much it.

Primary Sources. On an average day of research for Marc, I'll start [searching primary sources chronologically] with

a. MGT (if possible), then
b. GT (including IW), then
c. TNE (because I have to, not because I want to), then
d. MT, then
e. CT materials.

Within those materials, the primary publisher is the first source, but any licensee could be a secondary source.

Secondary Sources [and Ideas That Marc Likes]. Oh, and yes, 1248 goes in there somewhere. I wouldn't consider it a primary source, but definitely a secondary source. Heck, there's even a couple of Judges Guild items Marc mentions from time to time. Admittedly, I haven't dug much out of the JG/Group One/Paranoia Press materials for Marc, but I've got them to refer to. And even HIWG docs and fanzines COULD be a source if it's an idea that Marc likes. For example, I pay very close attention to HIWG docs written by Clay Bush on subjects. And I've got the TML and Xboat archives setup as searchable because they have clues to things I don't remember.

I cannot think of a single source that would be outright rejected with no consideration at all.

The Traveller Integrated Timeline isn't a source: it's a list of sources.

So, the moral is, don't throw rocks at other Traveller settings. We're all in the same tent, even if we imagine we're not.

Some things Marc has repeatedly said are NOT canon:

1. Anything under 100 tons jumping. 101-ton jump ships work, but 99-ton jump anythings simply don't.
2. Almost all Aslan art has the hands and paws wrong. I've repeatedly had this explained to me, but I still don't picture it properly.
3. There are only six major races, and they are all identified. Don't add another one.
4. DGP's pre-Ancient Primordials/Sparklers - including some of the material in Knightfall. Come on, Joe Fugate only briefly mentioned them in his goodbye.
5. Light sabers, ala Star Wars. This might be proof that Traveller and Star Wars have different physics foundations.
6. Simultaneous FTL communication is never possible. No combination of psionics, science or magic can produce this in the OTU.